This invention relates to a hydraulic device for barber's chair and the like.
A hydraulic device is commonly used for raising and lowering the seat of a barber's chair. The hydraulic device is cylindrical and forms a part of the support column for the seat of the chair. The seat is mounted onto the top portion of a sliding plunger of the device which has an elongated cantilever that may be operated by pivoting it up and down in a pumping action such that the sliding plunger would extend upwards slowly for raising the seat upwards accordingly. The hydraulic device has a cylindrical main housing section and a lower section. The main housing section is filled with operating oil; and the pumping action is to force the oil in the main housing section to move into the lower section and through an internal channel therein to thrust the sliding plunger upwards. The seat may be lowered slowly from the raised position by pressing on the operating lever so as to open a release valve therein to allow the oil in the lower section to return to the main housing section slowly, to lower the plunger and, in turn, lowering the seat accordingly. The lower section of the device is commonly mounted to the bottom of the main housing section with bolts and an O-ring is provided in the upper portion of the lower section to seal the joint formed by this upper portion engaging with the lower portion of the main housing section. The O-ring is intended to ensure the sealing of the joint to prevent the leakage of oil therethrough. However, due to fabrication tolerances of the different component parts and the unsatisfactory mounting force provided by the mounting bolts, it has been a plaguing problem with the leakage of oil through the joint. The oil leaked from the hydraulic device onto the floor of the barber shop presents a safety hazard to the barber and the customers since they may slip and fall on the oily floor. The leaked oil would also contaminate the environment; and would, in fact, eventually lead to the failure of the device due to insufficient amount of oil remaining in the pump. Furthermore, the rubber O-ring used in ensuring the sealing the joint inherently deteriorates with the exposure to the oil and resulting in the complete failure of the sealing provision of the joint.
Moreover, an additional circular groove must be formed at the upper portion of the lower section for retaining the O-ring in place. The formation of such circular groove requires further precision fabrication steps in the manufacturing of the lower section.